<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<link href="css/bootstrap.css" rel="stylesheet" />
	</head>
	<body>
		<div class="container">
			<div class="dropdown open">  <!-- open控制菜单收缩展开-->
				<button class="btn btn-primary " data-toggle="dropdown" >
					Dropdown
					<span class="caret"></span>    <!-- 向下小三角-->
				</button>
				<ul class="dropdown-menu">
					<li class="active"><a href="#">Action</a></li> <!-- active 默认是选中状态-->
					<li><a href="#">Another action</a></li>
					<li class="divider"></li>     <!-- 分界线-->
					<li><a href="#">Something else here</a></li>
					<li><a href="#">Separated link</a></li>
				</ul>
			</div>
		</div>
		<script src="js/jquery-1.12.4.js"></script>
		<script src="js/bootstrap.js"></script>
	</body>
</html>
